In this age of the growing importance of information, there is a great urgent demand for organic dye compounds which absorb short-wavelength visible radiation. Their application is now extending beyond conventional field, for example, filter material which solely utilize the visible radiation-absorbing and shielding property of such an organic dye compound, towards the field of information storage and solar power generation which utilize energy of visible radiation by such an organic dye compound.
The properties required for organic dye compounds to be subjected to such a use are to be appropriate with respect to optical absorption characteristic at short-wavelength visible region, large with respect to optical resistance, with respect to solubility in solvents and also with respect to heat characteristic according to its use Typical organic dye compounds as proposed heretofore are, for example, anthraquinone, phthalocyanine and cyanine dyes (see, for example, Japanese Patent Kokai Nos. 116611/99, 202592/02 and 167343/03): Among these, anthraquinone dye has been deemed to be disadvantageous with respect to optical absorption characteristic, while phthalocyanine dye, disadvantageous with respect to both optical absorption characteristic and solubility in solvents. Although cyanine dye is advantageous in both optical absorption characteristic and solubility, conventional cyanine dye has the demerit that it is poorer with respect to optical resistance and heat characteristic.
In view of such situation, the objective of this invention is to provide a novel organic dye compound which adsorbs short-wavelength visible radiation, superior in optical resistance and also in solubility in solvents and exhibits heat characteristic required in a novel field using the organic dye compound so as to extend the range of choosing organic dye compounds as radiation-absorbing organic material in the fields as described above.